Stabilization of hydrocarbon



Patented @ct. 24,1939 v um I) STATEVS PATENT OFFICE' STABILIZATION F HYDROCARBON COMPOUNDS Charles Harold Fisher, Pittsburgh, Pa., assignor to The Pennsylvania Coal Products 00., Petrolia, Pa., a corporation of Pennsylvania No Drawing. Application January 8, 1936, Serial No. 58,220. Renewed March 16, 1939 i, 23 Claims.

The present invention relates, in general, to the eral, gasolines containing benzol, motor benzols,

10 heavy motor fuels such as used in Diesel engines and the like, white or medicinal oil, coal tar distillates and the like, is not limited thereto, but may be practiced whenever it is desirable to stabilize the liquid hydrocarbons or their equivalents, and

especially in connection with motor fuels which exhibit a tendency to discolor and/or form gum,

' sludge and/or resinous products. The invention is especially valuable in the stabilization of gasoline derived from the cracking of petroleum.

: Many of the present day gasolines contain unsaturated compounds which are capable of oxidation on exposure to air to form various products, some of which are of a gummy or resinous character. While the presence of unsaturants is 5 the primary cause for many gasolines discoloring and forming gummy products, difierences in structure other than the degree of saturation do cause oxidation of the gasoline.

Many of the motor fuels, including gasoline, have chemicals added thereto for various pur- D poses including coloration and the prevention of knocking. For example, various dyes are added to gasoline to color the same and tetra ethyl lead is added as an anti-knock agent. Such chemicals increase the difiiculties attendant to the proper stabilization of the gasoline.

The present invention has for an object the stabilization of liquid hydrocarbons which because of various factors, whatever they may be, exhibit a tendency to discolor and form resinous and gummy products which prevent the hydrocarbon from functioning efiiciently for its intended purpose.

Another object is to stabilize such hydrocarbons for use as a motor fuel.

Still another object is to prepare a liquid hydrocarbon which contains a dye and which isstabilized against discoloration inthe presence of sunlight or its equivalent.

Still another object is to stabilize hydrocarbon motor fuels containing a dye and/or an antilmock agent,

The above objects and other objects, as will hereinafter appear, are accomplished by incorporating in the liquid hydrocarbon or the motor fuel, a small percentage of an alkyl hexahydroxy spiro-bis-indane compound, and more specifically, a tetra alkyl hexahydroxy indane compound, although other hexahydroxy spirobis-indanes having a greater number of alkyl radicals may be used.

One suitable tetra alkyl hexahydroxy indane compound suitable for carrying out the present invention is 3, 3, 3', 3' tetramethyl, 4, 6, 7, 4', 6', '7' hexahydroxy, 1, 1' spiro-bis-indane; which has been named in accordance with the nomenclature system of Chemical Abstracts of the American Chemical Society.

In one specific form of the invention, there is incorporated in the motor. fuel a small amount of the condensationproduct of a poly hydroxy phenol or derivatives thereof with a ketone, as for example, acetone. The poly hydroxy phenols areexemplifie'd by hydroxyhydroquinone, or by hydroxyhydroquinone triacetate. The condense: tion product of the hydroquinone acetate and acetone results in the formation of tetra alkyl hexahydroxy spiro-bis-indane. When pyrogallol is condensed with acetone, the following hexahydroxy spiro-bis-indane compounds are formed:

3' tetramethyl, 4, 5, 6, 4, 5, 6 hexahydroxy, l, l Spiro-bismdane,

and

3, s, 3', a tetramethyl, 5, a, 1, 5', 6, 7' hexahydroxy, '1, 1' s ire-bis. lndane.

- ketone (e. g., homologues of phorone,

A mixture is made of Hydroxy-hydroquinone triacetate A ketone, such as acetone (0.11 mole) gin 6.4]

A weak acid, such as acetic acid cc A strong mineral acid, such as 32% hydrochloric acid cc The mixture is heated for about one (1) hour at a temperature of about 50 C. until a complete solution is formed. The mixture is then allowed to stand from several hours until about five (5) days. The time that the mixture is allowed to stand'will depend on a number of factors, including the temperature at which the condensation reaction is carried out. The reaction time may be lowered by carrying out the reaction at an elevated temperature, reaction being apparently complete after six (6) hours at 75 C., while five (5) days in the cold may be necessary.

By the above procedure, the condensation is allowed to occur and the products of reaction separated from the solution by filtration The solid condensation product is purified; and when in its purified state, melts at about 266 to 267 C. The purification is effected by washing or crystallizing from suitable solvents such as acetic acid or alcohol.

The filtrate is again charged with new quantities of Hydroxy hydroquinone triacetate gm 1'7 Acetone -i gm 6.4

and the condensation reactions are repeated. To the liquor from the above condensation, additional raw materials, as above, are again added, together with an additional amount of concentrated hydrochloric acid. It will be sufiicient to add about 3 cc. or 4 cc. of hydrochloric acid to about 45 cc. of. the filtrate.

This procedure is repeated for ten (10) cycles, and preferably every other cycle an addition of a suitable amount of hydrochloric acid is made. After ten (10) runs, the liquor is very much contaminated with by-products, and, therefore, is discarded, or may be treated to recover by known methods the acetic acid present, and the ketone condensation products (such as homologues of.

mesityl oxide and phorone present).

One of the features of the above process of condensation is the production of the condensation product in a reaction medium wherein the liquors from the condensation reaction, after separation of the condensation products, are re'-used as a medium for further condensation reactions, upon fresh additions of the reacting constituents, such as a phenol and a ketone. While preferably the condensation is carried out in an .acid medium comprising a strong inorganic acid and a weak organic acid, other solvent mediums may be employed. It is desirable, although not absolutely necessary, to add an additional strong acid after several cycles of condensation. As stated above, it is preferred to add the strong mineral acid, such as hydrochloric acid, every other cycle, although obviously this will be governed somewhat by the character of the initial starting reaction medium. Tests can be made as to the strength of the acetic acid-hydrochloric acid condensation medium, and it may be brought up to strength as is necessary, whether this be every other cycle, or every third cycle, or otherwise.

In the above example, it has been stated that the condensation liquor is used as a medium for further condensation, but that after ten (10) runs the liquor is discarded, as it is contaminated with by-products. Here again, the figure of ten (10) runs is given as illustrative and this may be considerably varied. Tests will show when the condensation liquid should be discarded.

The batch given above is illustrative of suitable batches. It is highly desirable to keep the ratio of the poly hydroxy phenol or its alkyl ether to the ketone approximately as above specified, as any substantial change in the ratio produces a lower yield or a loss of ketone. The acetic acid or any other suitable medium, examples of which are hereinafter given, must be present in a relatively large proportion to act as a solvent for the by-products which are tarryand must necessarily be kept in solution. It is also desirable to keep the hydrochloric acid concentration, or other condensing agents used, ashereinafter specified, substantially constant, or nearly so.

While the use of acetic and hydrochloric acids, as given in the above example, are most satisfactory, condensation can be effected by using other condensation mediums. For example, the acetic acid may be eliminated and the reaction product later purified by washing in acetic acid or alcohol. Other solvents besides acetic acid may be used. Sulphuric acid or aluminum chloride may replace the hydrochloric acid, or the hydrochloric acid may be generated in situ by a mixture of salt and sulphuric acid.

It is desired to point out that the re-use of liquors in the cycle process disclosed results in a saving of acetic acid. Further, it is highly desirable to use thecyclic process and to re-use the liquors, since .the recovery of the acetic acid from the liquors proved to be exceedingly difficult, and, further, the re-use of the liquors reduces the cost of the hydrochloric acid consumed in the process.

Additionally, the yield is greater because of the unconverted phenol, such as hydroxy hydroquinone acetate, or similar compound, which is always present, remaining constant throughout 'all ten (10) cycles. The use of a plurality of cycles has the advantage that all the polyhydric phenol added after the first cycle enters into the condensation reaction.

' In general, it may be stated that the process of preparing the above or similar phenol. ketone condensation products, is fiexible, and is not in any feature limited to the conditions set forth. As stated, the same products may be obtained by omitting the acetic acid from the batch, by using other quantities of the reagents by substituting other solvents forthe acetic acid, or by using other well known condensing agents in place of hydrochloric acid, as for example, sulphuric acid, aluminum chloride, and a mixture of salt and sulphuric acid, and the like.

rThe' above process introduces economies in operation and results in relatively high yields.

The compound produced by the above condensation reaction may be designated as a hexahydroxy derivative of alkyl spiro-bis-indane, and more specifically, 3,3,3',3' tetramethyl, 4,6,7,4',6',7' hexahydroxy, 1,1 spiro-bis-indane.

The hexahydroxy derivatives of alkyl spiro-bisindane produced by reacting a poly hydroxy phenol or its alkyl other with a ketone, such as acetone or methyl ethyl ketone, are in general white or light-colored solids melting usually at high temperatures. acetone, and moderately soluble in alcohol and chloroform, and slightly soluble in gasoline and the like.

It is desired to point out that the tetramethyl The products are soluble in ease of oxidation in certain types of gasoline.

This is very important. The condensation of phenols with ketones having molecular weights greater than acetone, producesspiro-bis-lfidane compounds having larger or heavier alkyl groups than the methyl group, than would be present if the condensation had been effected with acetone. It has been found, in general, that the spiro-bis-indane compounds containing larger or heavier groups have increased solubility in organic materials, such as gasoline, and are less soluble in water, thus lessening the tendency of the spiro-bis-indane to be removed by water.

A tetra-alkyl hexahydroxy spiro-bis-indane compound produced by the above method, or by any other method, may be incorporated in a small amount in a liquid hydrocarbon and functions to inhibit discoloration and the formation of gummy and resinous products. It is particularly adapted to so function when added to motor fuels. It is sufiiciently soluble therein to be added directly, and may be incorporated in the motor fuel in amounts ranging from 0.0005 to .01 per cent based on the weight of the motor fuel. In practice, the amount of inhibitor present may be rated in terms of grams per gallon of motor fuel to be stabilized. This usually varies between 0.025 to 0.3 gm. per gallon of fuel treated. In one form of the invention the spiro-bis-indane may be dissolved in a solvent exemplified by acetone or alcohol, and said solvent containing the indane added to the motor fuel. For example, 1 part by weight, of the inhibitor may be dissolved in 3 parts, by weight, of acetone, or 10 parts, by weight, of alcohol. If the inhibitor is dissolved in acetone (3 parts by weight), then to a gallon of gasoline, there should be added from 0.1 gm. to

1.2 gms. of this mixture. If the inhibitor is dissolved in 10 parts of alcohol then 0.27 gm. to 3.3 gms, of the alcohol mixture should be added to a gallon of gasoline.

It '.is desired to point out that the herein disclosed tetra-alkyl hexahydroxy splro-bis-indane is only slightly soluble in water, and, therefore, its use is decidedly advantageous over those inhibitors which are'soluble to a large extent in water.

It is to be understood that the amount of tetraalkyl hexahydroxy spiro-bis-indane added to the motor fuel may be varied from that specified in the illustrative example above set forth. In practice, the amount of inhibiting agent which is added to the motor fuel, will depend upon many factors including the nature of the hydrocarbon fuel, the temperature thereof and the condition of storage It will be understood that in any case the compound is used in a comparatively small quantity, and when used in comparatively small amounts of the order of those above pointed out, it is substantially less than would deposit gum.

The 3,3,3',3' tetramethyl and 4,6,7,4',6,7' hexahydroxy, 1,1 spiro-bis indane, and the other spiro-bis-indanes herein referred to are exemplary of suitable tetraalkyl hexahydroxy compounds which may be used as a stabilizer for the motor fuel. Other alkyl radicals, saturated'or unsaturated, may be substituted for the methyl radical. 1

It is desired to point out that during the condensation process, it is possible to form several isomers. l

While it has been' found particularly desirable thatthe mixed aim l radicals be the methyl and ethyl radicala'othez' equivalent alkyl radicals may be introduced into the rings, said-alkyl radicals being saturated or unsaturated Motor fuels treated in accordance with the present invention not only test up well on the copper dish andinduction period tests, but st and storage successfully, without going off color 1mder drastic exposure to light and regardless of the presence of other chemicals, such as lead tetraethyl and organic dyes.

Transformer oil, which is used in the electrical industry, may be treated with the present stabilizer.

The present invention is applicable to the stabilization of'hydrocarbon fuels having an aromatic base or an aliphatic base.

The 3,3,3'.3 tetramethyl, 4,6,7,4',6',7 hexahydroxy 1,1' spiro-bis-indane may be represented structurally as follows:

0H, OH; OH 0 4 Ax 5 6 2 H1 H0 1 l/OH H CH;

Usually, only one of the hydroxy spiro-bis -in danes is added to the hydrocarbon, and in some cases it may be advantageous to employ mixtures of different hydroxy spiro-bis-indanes. Any of the alkyl hydroxy spiro indanes herein set forth may be mixed together and added to the hydrocarbon. More specifically, there may be added to the hydrocarbon a mixture of different alkyl hexahydroxy spiro-bis-indanes. Y For example, there may be added to the hydrocarbon a mixture of tetra-methyl hexahydroxy spiro-bisindane and tetramethyl ethyl hexahydroxy spirobis-indane.

I claim: v

1. A liquid hydrocarbon of a type normally tending to discolor and form gum during storage containing a small amount of a tetra alkyl hexahydroxy spiro-bis-indane.

2. A liquid hydrocarbon of a type normally tending to discolor and form gum during storage containing as astabilizing agent a small amount of a tetra alkyl hexahydroxy spiro-bis-indane.

3. A liquid hydrocarbon of a type normally tending to discolor and form gum during storage containing as a stabilizing agent a small amount of a tetramethyl hexahydroxy spiro-bis-indane.

4. Gasoline derived from the cracking of petroleum and containing as a stabilizing agent a small amount of t'etr'a alkyl hexahydroxy spirobis-indane.

5. Gasoline derived from the cracking of petroleum and containing as a stabilizing agent a small amount of tetramethyl hexahydroxy spiro-.

, 9. Gasoline derived from the cracking of petroleum and containing as a stabilizing agent 0.0005

to 0.01 per cent of a tetramethyl hexahydroxy spiro-bis-indane.

10. A liquid hydrocarbon of a type normally tending to discolor and form gum during storage containing as a stabilizing agent a small amount of 3,3-,3',3 tetramethyl, 4,6,'7,4',6','I hexahydroxy 1,1 spiro-bis-indane.

11. Gasoline derived from the cracking of petroleum containing a small amount of 3,3,3',3 tetramethyl, 4,6,'7,4',6',7 hexahydrox'y 1,1 spirobis-indane. 7

12. A new composition of matter comprising a hydrocarbon fuel of a type normally tending to discolor and form gum during storage and as a stabilizer, a small amount of a tetra alkyl hexahydroxy spiro-bis-indane. I

13. A new composition of matter comprising a hydrocarbon fuel of a type normally tending to discolor and form gum during storage and as a stabilizer, a small amount of a tetramethyl hexahydroxy spiro-bis-indane.

14. A new composition of matter comprising a hydrocarbonmotor fuel of a type normally tending to discolor and form gum during storage containing a small amount of 3,3,3,3 tetramethyl,

4,6,'7,4,6',7' hexahydroxy 1,1 spiro-bis-indane.

15. A new composition of matter comprising a hydrocarbon-motor fuel of a type normally tending to discolor and form gum during storage, andas a stabilizer 0.0005 to 0.01 per cent of 3,3,3',3' tetramethyl, 4,6,'1,4',6',7' hexahydroxy 1,1 spiro-bis-indane.

16. A mixed motor fuel of a type normally tending to discolor and. form gum during storage including gasoline and petroleum and containing as a stabilizer a small quantity of tetra alkyl hexahydroxy spiro-bis-indane.

17. The process of inhibiting discoloration and/or formation of gum in a motor fuel comprising adding to the motor fuel a small quantity of tetra alkyl hexahydroxy spiro-bis-indane.

18. The process of inhibiting discoloration and/or formation of gum in a motor fuel comprising adding to the motor fuel a small quantity of tetramethyl hexahydroxy spiro-bis-indane.

19. The process of inhibiting discoloration and/ or formation of gum in a motor fuel comprising adding to the motor fuel a small quantity of 3,3,3',3' tetramethyl, 4,6,7,4,6,'7' hexahydroxy, 1,1 spiro-bis-indane.

20. The process of inhibiting discoloration and/or formation of gum in a motor fuel comprising adding to the motor fuel a small quantity of alkyl hexahydroxy spiro-bis-indane.

21. A liquid hydrocarbon of a type normally tending to discolor and form gum during storage containing a small amount of alkyl hexahydroxy spiro-bis-indane.

22. The process of inhibiting discoloration and/or formation of gum in a motor fuel comprising adding to the motor fuel a small quantity of a mixture of alkyl hexahydroxy spiro-bis-indanes.

23. A liquid hydrocarbon of a type normally tending to discolor and form gum during storage containing a small amount of a mixture of alkyl hexahydroxy spiro-bisindanes.

CHARLES HAROLD FISHER. 

